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| United States Patent |
6,207,335
|
|
Michel
, et al.
|
March 27, 2001
|
Use of metal carboxylates and sulfonates as charge control agents
Abstract
Use of metal carboxylates and sulfonates as charge control agents Metal
carboxylates and metal sulfonates are employed as charge control agents in
electrophotographic toners and developers, as charge improvers in powder
coating materials and electret materials, and in electrostatic separation
processes.
| Inventors:
|
Michel; Eduard (Frankfurt, DE);
Baur; Ruediger (Eppstein, DE);
Macholdt; Hans-Tobias (Darmstadt, DE)
|
| Assignee:
|
Clariant GmbH (Frankfurt, DE)
|
| Appl. No.:
|
376029 |
| Filed:
|
August 17, 1999 |
Foreign Application Priority Data
| Aug 19, 1998[DE] | 198 37 522 |
| Current U.S. Class: |
430/114 |
| Intern'l Class: |
G03G 9/0/97 |
| Field of Search: |
430/106,109,110
|
References Cited
U.S. Patent Documents
| 4276154 | Jun., 1981 | Singewald et al. | 209/3.
|
| 4367275 | Jan., 1983 | Aoki et al. | 430/110.
|
| 4403027 | Sep., 1983 | Ishikawa et al. | 430/110.
|
| 4407924 | Oct., 1983 | Senshu et al. | 430/109.
|
| 5294682 | Mar., 1994 | Fukuda et al. | 430/110.
|
| 5300387 | Apr., 1994 | Ong | 430/110.
|
| 5314778 | May., 1994 | Smith et al. | 430/111.
|
| 5346793 | Sep., 1994 | Bertrand et al. | 430/110.
|
| 5378571 | Jan., 1995 | Macholdt et al. | 430/110.
|
| 5484678 | Jan., 1996 | Pickering et al. | 430/110.
|
| 5562755 | Oct., 1996 | Fricke et al. | 95/58.
|
| 5571654 | Nov., 1996 | Ong | 430/110.
|
| 5871845 | Feb., 1999 | Dahringer et al. | 428/378.
|
| Foreign Patent Documents |
| 26 19 026 | Nov., 1977 | DE.
| |
| 4321289 | Jan., 1995 | DE.
| |
| 0 201 340 | Nov., 1986 | EP.
| |
| 0 623 941 | Mar., 1994 | EP.
| |
| 5-163449 | Jun., 1993 | JP.
| |
| WO 92/06414 | Apr., 1992 | WO.
| |
Other References
EPO Search Report.
European Patent Office Abstract of Japan 62163061.
Derwent Patent Family Report and/or Abstract.
"The Effect of an Externally Added Charge Control Agent on Contact Charging
Between Polymers," Y. Higashiyama, G. Castle, I. Inculet, and J.D. Brown,
Journal of Electrostatics, 30 (1993), pp. 203-212.
"Selektives Trennen von Salzmineralen aufgrund spezifischer
Oberflachen-Eigenschaften," A. Singewald and L. Ernst, Zeitschrift Fur
Physikalische Chemie Neue Folge, vol. 124 (1981), pp. 223-248).
|
Primary Examiner: Goodrow; John
Attorney, Agent or Firm: Jackson; Susan S., Hanf; Scott E.
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
The present invention is described in the German priority application No.
198 37 522.0, filed Aug. 19, 1998, which is hereby incorporated by
reference as is fully disclosed herein.
Claims
What is claimed is:
1. A method of controlling and improving the charge in electrophotographic
toners and developers, in powder coating materials, in electret materials
and in electrostatic separation processes, comprising adding thereto a
metal carboxylate or metal sulfonate of the formula (1), (2) or (2a),
##STR12##
in which
A.sup.10 is an acid radical of acid A.sup.1 as defined below;
A.sup.20 is an acid radical of acid A.sup.2 as defined below;
A.sup.30 is as defined for A.sup.10 or A.sup.20 ;
M.sup.2 is a divalent metal cation, and
M.sup.3 is a trivalent metal cation,
wherein
A.sup.1 is
a) an acid of fornulae (I) to (VIII)
##STR13##
in which
R.sup.1 is a linear or branched alkyl radical with 1 to 18 carbon atoms,
R.sup.2 and R.sup.3 are identical or different and are hydrogen, C.sub.1
-C.sub.8 -alkyl, (C.sub.1 -C18)-hydroxyalkylene, nitro, cyano, fluoro,
chloro, bromo, C.sub.1 -C.sub.4 -acyl, C.sub.6 -C.sub.10 -aryl,
heteroaryl, it being possible for aryl and heteroaryl to be substituted by
from 1 to 3 of the radicals carboxyl, hydroxyl, C.sub.1 -C.sub.4 -alkoxy,
C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -acyl, halogen, hydroxy-(C.sub.1
-C.sub.4)-alkyl and amino,
##STR14##
in which
R.sup.4, R.sup.5 and R.sup.6 are identical or different and are hydrogen,
C.sub.1 -C.sub.8 -alkyl, (C.sub.1 -C.sub.18)-hydroxyalkylene, nitro,
cyano, fluoro, chloro, bromo, C.sub.1 -C.sub.4 -acyl, C.sub.6 -C.sub.10
-aryl, heteroaryl, it being possible for aryl and heteroaryl to be
substituted from 1 to 3 of the radicals carboxyl, hydroxyl, C.sub.1
-C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkyl, halogen, hydroxy-(C.sub.1
-C.sub.4)-alkyl and amino,
m is 1, 2 or 3, and
n is O, 1 or 2;
b) a heteroaromatic mono- or dicarboxylic acid;
c) a polyanion-forning compound selected from the group consisting of
poly(styrenesulfonic acid), poly(acrylic acid), poly(methacrylic acid),
poly(maleic acid), poly(anetholesulfonic acid), poly(itaconic acid),
poly(vinyl sulfate), poly(vinylsulfonic acid), poly(acrylic acid-co-maleic
acid), poly(styrenesulfonic acid-co-maleic acid), poly(ethylene-co-acrylic
acid), hectorite, bentonite, algic acid, pectic acid, kappa-, lambda-, and
iota-carrageenans, xanthan, gum arabic, dextran sulfate,
carboxymethyldextran, carboxymethylcellulose, cellulose sulfate, starch
sulfate, lignosulfonates, gum karaya; polygalacturonic acid,
polyglucuronic acid, polyguluronic acid, polymannuronic acid and
copolymers thereof, chondroitin sulfate, heparin, heparan sulfate,
hyaluronic acid, dermatan sulfate, keratan sulfate; and derivatives of
starch, amylose, amylopectin, cellulose, guaran, gum arabic, gum karaya,
guar gum, pullulan, xanthan, dextan, curdlan, gellan, carubin, agarose,
chitin, and chitosan having the following functional groups:
carboxymethyl, carboxyethyl, carboxypropyl, 2-carboxyvinyl,
2-hydroxy-3-carboxypropyl, 1,3dicarboxyisopropyl, sulfomethyl,
2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 5-sulfopentyl,
2-hydroxy-3-sulfopropyl, 2,2-disulfoethyl, 2-carboxy-2-sulfoethyl,
maleate, succinate, phthalate, glutarate, aromatic and aliphatic
dicarboxylates, xanthogenate, sulfate, phosphate, 2,3-dicarboxy,
N,N-di(phosphatomethyl)aminoethyl, N-alkyl-N-phosphatomethyl-aminoethyl,
it also being possible for these to contain methyl, ethyl, propyl,
isopropyl, 2-hydroxyethyl, 2-hydroxypropyl and 2-hydroxybutyl groups and
also esters with aliphatic carboxylic acids (C.sub.2 to C.sub.18);
and of the formula (X)
##STR15##
where n=5 to 5.times.10.sup.5 ; and R.sup.1, X, A and Y are each identical
or different and defined as follows:
R.sup.1 =H or CH.sub.3 ;
X=O or NH;
A=branched or linear (C.sub.1 -C.sub.18)alkylenes or arylenes;
Y=SO.sub.3, COO, N.sup..rho. R.sup.3.sub.2 --A--COO, N.sup..rho. R.sub.2
--A--SO.sub.3.sup..sigma., N.sup.(2 R.sup.3.sub.2 --A--PO(OH)O.sup..sigma.
where R.sup.3 =C.sub.1 -C.sub.8)-alkyl;
and also copolymers consisting of monomers of the abovementioned compounds
and one or more of the following monomers: acrylic acid, methacrylic acid,
acrylic acid alkyl-(C.sub.1 -C.sub.18)-ester, methacrylic acid
alkyl(C.sub.1 -C.sub.18) ester, glycidyl methacrylate, acrylamide,
acrylonitrile, methacrylonitrile, ethylene, styrene,
.alpha.-methylstyrene, styrenesulfonic acid, butadiene, butene, isoprene,
vinyl chloride, propylene, maleic anhydride, maleic acid, maleic acid
monoalkyl(C.sub.1 -C.sub.18) or dialkyl-(C.sub.1 -C.sub.18) ester, alkyl-(
C.sub.1 -C.sub.18) vinyl ether, vinyl alcohol, vinyl acetate,
vinylbutyral, vinylimidazole, N-vinyl-2-caprolactam, N-vinylpyrrolidone,
mono- or dialkylated (C.sub.1 -C.sub.30) N-vinylpyrrolidone, vinylsulfonic
acid, diallydimethylammonium chloride, vinylidene chloride, poly(ethylene
glycol) methacrylate, poly(ethylene glycol) acrylate;
d) a carboxyl- and/or sulfo-containing polyester,
A.sup.2 is an acid of formulae (I) to (VIII);
an acid of formula (IX)
##STR16##
in which R.sup.4 and R.sup.5 are as defined above;
or a heteroaromatic mono- or dicarboxylic acid;
or by reacting an acid A.sup.1 as defined in c) or d) with an acid A.sup.2
in the definition of the formulae (I) to (IX) in which R.sup.1 to R.sup.6
have the definitions specified above and in addition the definition
(C.sub.1 -C.sub.18)-alkoxy, hydroxyl, amino, (C.sub.1
-C.sub.18)alkylamino, di(C.sub.1 -C.sub.18)alkylamino, (C.sub.1
-C.sub.18)alkylene-NR.sup.7 R.sup.8, in which R.sup.7 and R.sup.3 are
hydrogen or C.sub.1 -C.sub.8 -alkyl; and the cation of the metal is
divalent or trivalent.
2. The method as claimed in claim 1, wherein M.sup.2+ is Fe.sup.2+,
Zn.sup.2+, Co.sup.2+, Ni.sup.2+, Mn.sup.2+, Cu.sup.2+, Mg.sup.2+,
Ca.sup.2+, Sr.sup.2+ or Ba.sup.2+.
3. The method as claimed in claim 1, wherein M.sup.3+ is A.sup.1.sup.3+,
Fe.sup.3+, Mn.sup.3+, or Co.sup.3+.
4. The method as claimed in claim 1, wherein A.sup.1 is a compound of the
formula
##STR17##
##STR18##
c) poly(methacrylic acid), poly(styrenesulfonic acid),
poly(ethylenesulfonic acid), poly(styrenesulfonic acid-co-maleic acid
1:1),
d) polyester consisting of the reaction product of the individual
components i), ii) and iii) and optionally, iv) and, optionally, v), where
i) is a dicarboxylic acid or a reactive derivative of a dicarboxylic acid
which is free from sulfo groups,
ii) is a difimctional aromatic, aliphatic or cycloaliphatic sulfo compound
whose functional groups are hydroxyl or caiboxyl, or hydroxyl and
carboxyl,
iii) is an aliphatic, cycloaliphatic or aromatic diol, a polyether diol or
a polycarbonate diol,
iv) is a polyfunctional compound (functionality >2), whose functional
groups are hydroxyl or carboxyl, or hydroxyl and carboxyl, and
v) is a monocarboxylic acid or a sulfo-containing monoalcohol.
5. The method as claimed in claim 1, wherein A.sup.2 is a compound of the
formula
##STR19##
##STR20##
6. The method as claimed in claim 1, wherein the metal carboxylate or metal
sulfonate is a compound of the formula (1) or (2a) in which
A.sup.10 is 4-tert-butylbenzoate, poly(ethylenesulfonate),
poly(methacrylate), diphenyl disulfide 2,2'-dicarboxylate or
poly(styrenesulfonate);
A.sup.20 is 4-tert-butylbenzoate, diphenyl disulfide 2,2'-dicarboxylate or
salicylate;
M.sup.2+ is Zn.sup.2+ and M.sup.3+ is Al.sup.3+.
7. The method as claimed in claim 1, wherein the metal carboxylate or metal
sulfonate is employed in combination with a further charge control agent
selected from the group consisting of triphenylmethanes, ammonium and
immonium compounds, iminium compounds, fluorinated ammonium and
fluorinated immonium compounds; biscationic acid amides; polymeric
ammonium compounds; diallylammonium compounds; aryl sulfide derivatives,
phenol derivatives; phosphonium compounds and fluorinated phosphonium
compounds; calix(n)arenes, cyclically linked oligosaccharides,
interpolyclectrolyte complexes, polyester salts; benzimidazolones; azines,
thiazines or oxazines, or metal azo complex dyes.
8. The method as claimed in claim 1, wherein the overall concentration of
metal carboxylate and metal sulfonate and further charge control agents if
added is from 0.01 to 50% by weight, based on the overall mixture of the
electrophotographic toner, developer, power coating material or electret
material.
9. The method as claimed in claim 1, wherein the overall concentration of
metal carboxylate and metal sulfonate and further charge control agents if
added is from 0.1 to 5% by weight, based on the overall mixture of the
electrophotographic toner, developer, power coating material or electret
material.
10. An electrophotographic toner comprising a metal carboxylate or metal
sulfonate as set forth in claim 1 and, optionally, one or more positive or
negative charge control agents in an overall concentration of from 0.01 to
50% by weight, based on the overall weight of the toner, and a customary
toner binder.
11. The electrophotographic toner as claimed in claim 10, additionally
comprising from 1 to 10% by weight of colorant, based on the overall
weight of the electrophotographic toner.
12. A powder coating material comprising a metal carboxylate or metal
sulfonate as set forth in claim 1 and, optionally, one or more positive or
negative charge control agents in an overall concentration of from 0.01 to
50% by weight, based on the overall weight of the powder coating material,
and a customary powder coating binder.
13. The powder coating material as claimed in claim 12, further comprising
from 1 to 10% by weight of colorant, based on the overall weight of the
powder coating material.
Description
BACKGROUND OF THE INVENTION
The present invention lies within the technical field of charge control
agents in toners and developers for electrophotographic recording
processes, in powders and powder coating materials for surface coating,
and in electret materials, especially in electret fibers, and in
separation processes.
In electrophotographic recording processes a latent charge image is
produced on a photoconductor. This latent charge image is developed by
applying an electrostatically charged toner which is then transferred to,
for example, paper, textiles, foils or plastic and is fixed by means, for
example, of pressure, radiation, heat or the action of solvent. Typical
toners are one- or two-component powder toners (also known as one- or
two-component developers); also used are speciality toners, such as
magnetic toners, liquid toners or polymerization toners, for example. By
polymerization toners are meant those toners which are formed by, for
example, suspension polymerization (condensation) or emulsion
polymerization and lead to improved particle properties in the toner. Also
meant are those toners produced basically in nonaqueous dispersions.
One measure of the quality of a toner is its specific charge q/m (charge
per unit mass). In addition to the sign and level of the electrostatic
charge, the principal, decisive quality criteria are the rapid attainment
of the desired charge level and the constancy of this charge over an
extended activation period. In addition to this, the insensitivity of the
toner to climatic effects such as temperature and atmospheric humidity is
a further important criterion for its suitability.
Both positively and negatively chargeable toners are used in copiers and
laser printers, depending on the type of process and type of apparatus.
To obtain electrophotographic toners or developers having either a positive
or negative charge, it is common to add charge control agents. Since the
charge of toner binders is in general heavily dependent on the activation
period, the function of a charge control agent is, on the one hand, to set
the sign and level of the toner charge and, on the other hand, to
counteract the charge drift of the toner binder and to provide for
constancy of the toner charge.
Charge control agents which are not able to prevent the toner or developer
from showing a high charge drift (ageing) during a prolonged period of
use, and which even cause the toner or developer to undergo charge
inversion, are hence unsuitable for practical use.
Another important practical requirement is that the charge control agents
should have sufficient thermal stability and good dispersibility. Typical
temperatures at which charge control agents are incorporated into the
toner resins, when using kneading apparatus or extruders, are between
100.degree. C. and 200.degree. C. Accordingly, thermal stability at
200.degree. C. is of great advantage. It is also important for the thermal
stability to be ensured over a relatively long period (about 30 minutes)
and in a variety of binder systems. This is significant because matrix
effects occur again and again and lead to the premature decomposition of
the charge control agent in the toner resin, causing the toner resin to
turn dark yellow or dark brown and the charge control effect to be wholly
or partly lost. Typical toner binders are addition polymerization,
polyaddition and polycondensation resins, such as styrene,
styrene-acrylate, styrene-butadiene, acrylate, polyester and phenol-epoxy
resins, and also cycloolefin copolymers, individually or in combination,
which may also include further components, examples being colorants, such
as dyes, pigments, waxes or flow assistants, or may have these components
added subsequently, such as highly disperse silicas.
Apart from their use in electrophotographic toners and developers, charge
control agents may also be used to improve the electrostatic charge of
powders and coating materials, especially in triboelectrically or
electrokinetically sprayed powder coating materials as are used to coat
surfaces of articles made from, for example, metal, wood, plastic, glass,
ceramic, concrete, textile material, paper or rubber. Powder coating
technology is used, for example, when coating articles such as garden
furniture, camping equipment, domestic appliances, vehicle parts,
refrigerators and shelving and for coating workpieces of complex shape.
The powder coating material, or the powder, receives its electrostatic
charge, in general, by one of the two following methods:
In the case of the corona method, the powder coating material or powder is
guided past a charged corona and is charged in the process; in the case of
the triboelectric or electrokinetic method, the principle of frictional
electricity is utilized.
The powder coating material or powder in the spray apparatus receives an
electrostatic charge which is opposite to the charge of its friction
partner, generally a hose or spray pipe made, for example, from
polytetrafluoroethylene.
It is also possible to combine the two methods. Typical powder coating
resins employed are epoxy resins, carboxyl- and hydroxyl-containing
polyester resins, polyurethane resins and acrylic resins, together with
the customary hardeners. Resin combinations are also used. For example,
epoxy resins are frequently employed in combination with carboxyl- and
hydroxyl-containing polyester resins.
The disadvantage of insufficient charging can be seen above all in
triboelectrically or electrokinetically sprayed powders and powder coating
materials which have been prepared using polyester resins, especially
carboxyl-containing polyesters, or using so-called mixed powders, also
referred to as hybrid powders. By mixed powders are meant powder coating
materials whose resin base consists of a combination of epoxy resin and
carboxyl-containing polyester resin. The mixed powders form the basis for
the powder coating materials used most commonly in practice. Inadequate
charging of the abovementioned powders and powder coating materials
results in an inadequate deposition rate and inadequate throwing power on
the workpiece to be coated. The term "throwing power" is a measure of the
extent to which a powder or powder coating material is deposited on the
workpiece to be coated, including its rear faces, cavities, fissures and,
in particular, its inner edges and corners.
It has additionally been found that charge control agents are able to
improve considerably the charging and the charge stability properties of
the electret materials, especially electret fibers (DE-A43 21 289).
Electret fibers have hitherto been described mainly in connection with the
problem of filtering very fine dusts. The filter materials described
differ both in respect of the materials of which the fibers consist and
with regard to the manner in which the electrostatic charge is applied to
the fibers. Typical electret materials are based on polyolefins,
halogenated polyolefins, polyacrylates, polyacrylonitriles, polystyrenes
or fluoropolymers, for example polyethylene, polypropylene,
polytetrafluoroethylene and perfluorinated ethylene and propylene, or on
polyesters, polycarbonates, polyamides, polyimides, polyether ketones, on
polyarylene sulfides, especially polyphenylene sulfides, on polyacetals,
cellulose esters, polyalkylene terephthalates, and mixtures thereof.
Electret materials, especially electret fibers, can be used, for example,
to filter (very fine) dusts. The electret materials can receive their
charge in a variety of ways, for instance by corona or triboelectric
charging.
It is additionally known that charge control agents can be used in
electrostatic separation processes, especially in processes for the
separation of polymers. For instance, using the example of the externally
applied charge control agent trimethylphenylammonium tetraphenyl borate,
Y. Higashiyama et al. (J. Electrostatics 30, (1993) 203-212) describe how
polymers can be separated from one another for recycling purposes. Without
charge control agents, the triboelectric charging characteristics of
low-density polyethylene (LDPE) and high-density polyethylene (HDPE) are
extremely similar. Following the addition of charge control agent, LDPE
takes on a highly positive and HDPE a highly negative charge, and the
materials can thus be separated easily. In addition to the external
application of the charge control agents it is also possible to conceive
in principle of their incorporation into the polymer in order, for
example, to shift the position of the polymer within the triboelectric
voltage series and to obtain a corresponding separation effect. In this
way it is possible to separate other polymers as well, such as
polypropylene (PP) and/or polyethylene terephthalate (PET) and/or
polyvinyl chloride (PVC), from one another.
Salt minerals, for example, can likewise be separated with particularly
good selectivity if they are surface-treated beforehand (surface
conditioning) with an additive which improves the substrate-specific
electrostatic charging (A. Singewald, L. Ernst, Zeitschrift fur Physikal.
Chem. Neue Folge, Vol. 124 (1981) 223-248). Charge control agents are
employed, furthermore, as "electroconductivity providing agents" (ECPAs)
in inks for inkjet printers (JP 05 163 449-A).
Charge control agents are known from numerous literature references.
However, the charge control agents known to date have a number of
disadvantages, which severely limit their use in practice or even, in some
cases, render it impossible; examples of such disadvantages are inadequate
thermal stability, inherent odor, poor dispersibility or low stability in
the toner binder (decomposition, migration). A particular weakness of many
common commercial charge control agents is the inadequacy of their
activity with respect to the desired sign of the charge (positive or
negative charge), charge level or charge constancy.
A further important aspect is that charge control agents should be
ecotoxicologically unobjectionable.
SUMMARY OF THE INVENTION
The object of the present invention was therefore to find particularly
effective and ecotoxicologically compatible charge control agents. The
intention is that the compounds should not only permit the rapid
attainment and constancy of the charge but should also be of high thermal
stability. Furthermore, these compounds should be readily dispersible,
without decomposition, in various toner binders employed in practice, such
as polyesters, polystyrene-acrylates or polystyrene-butadienes/epoxy
resins and also cycloolefin copolymers. Furthermore, their action should
be largely independent of the resin/carrier combination, in order to open
up broader applicability. They should likewise be readily dispersible,
without decomposition, in common powder coating binders and electret
materials, such as polyester (PES), epoxy, PES-epoxy hybrid, polyurethane,
acrylic systems and polypropylenes.
In terms of their electrostatic efficiency the charge control agents should
be active even at very low concentration (1% or less) and should not lose
this efficiency when in conjunction with carbon black or other colorants.
Indeed, it is known of colorants that they can affect--in some cases
lastingly--the triboelectric charging of toners.
A negatively charged toner consisting of toner resin, colorant and a
metallic additive for charge enhancement, obtainable from the reaction of
a metal ion with one molar equivalent of an ortho-hydroxyphenol and two
molar equivalents of an aromatic carboxylic acid in aqueous solution in
the presence of a base, is described in U.S. Pat. No. 5,571,654.
A toner consisting of resin, pigment and a three-way mixture as charge
additive, in which the side chain of an aromatic carboxyl compound
represents an alkoxy group, is described in U.S. Pat. No. 5,484,678.
Finally, U.S. Pat. No. 5,346,793 describes a negatively charged toner
consisting of resin particles, pigment particles and a charge enhancing
additive obtainable from the reaction of an inorganic aluminum salt
solution and an alkoxy-substituted benzoic acid.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Surprisingly it has now become evident that metal carboxylates and metal
sulfonates defined below have good charge control properties, especially
for negative charges and high thermal stability, the charge control
property being lost neither by combination with carbon black nor by a
combination with other colorants. Furthermore, the compounds are readily
compatible with the customary toner, powder coating and electret binders
and are easy to disperse.
The present invention provides for the use of metal carboxylates and metal
sulfonates as charge control agents in electrophotographic toners and
developers, as charge improvers in powder coating materials, electret
materials and in electrostatic separation processes, the metal
carboxylates and metal sulfonates being prepared by reacting an acid
A.sup.1 and an acid A.sup.2 in an aqueous alkaline medium, or by reacting
an alkali metal salt of the acid A.sup.1 and of the acid A.sup.2, with a
water-soluble metal salt, wherein A.sup.1 is
a) an acid of formulae (I) to (VIII)
##STR1##
in which
R.sup.1 is a linear or branched alkyl radical with 1 to 18 carbon atoms,
R.sup.2 and R.sup.3 are identical or different and are hydrogen, C.sub.1
-C.sub.8 -alkyl, (C.sub.1 -C,.sub.8)-hydroxyalkylene, C.sub.6 -C.sub.10
-aryl, heteroaryl, e.g. pyridyl, imidazolyl, pyrazolyl, quinolinyl,
isoquinolinyl, benzimidazolyl or indolyl, it being possible for aryl and
heteroaryl to be substituted by from 1 to 3 of the radicals carboxyl,
hydroxyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkyl, C.sub.1
-C.sub.4 -acyl, halogen, hydroxy-(C.sub.1 -C.sub.4)-alkyl and amino, or
are nitro, cyano, fluoro, chloro, bromo or C.sub.1 -C.sub.4 -acyl;
##STR2##
in which
R.sup.4, R.sup.5 and R.sup.6 are identical or different and are hydrogen,
C.sub.1 -C.sub.8 -alkyl, (C.sub.1 -C.sub.8)-hydroxyalkylene, C.sub.6
-C.sub.10 -aryl, heteroaryl, e.g. pyridyl, imidazolyl, quinolinyl,
isoquinolinyl or benzimidazolyl, it being possible for aryl and heteroaryl
to be substituted from 1 to 3 of the radicals carboxyl, hydroxyl,
C,-C.sub.4 -alkoxy, C,-C.sub.4 -alkyl, halogen, hydroxy-(C.sub.1
-C.sub.4)-alkyl and amino, or are nitro, cyano, fluoro, chloro, bromo or
C.sub.1 -C.sub.4 -acyl;
m is 1, 2 or 3, and
n is 0, 1 or 2;
b) a heteroaromatic mono- or dicarboxylic acid;
c) a polyanion-forming compound from the group consisting of
poly(styrenesulfonic acid), poly(acrylic acid), poly(methacrylic acid),
poly(maleic acid), poly(anetholesulfonic acid), poly(itaconic acid),
polylvinyl sulfate), poly(vinylsulfonic acid), poly(acrylic acid-co-maleic
acid), poly(styrenesulfonic acid-co-maleic acid), poly(ethylene-co-acrylic
acid), hectorite, bentonite, algic acid, pectic acid, kappa-, lambda-, and
iota-carrageenans, xanthan, gum arabic, dextran sulfate,
carboxymethyidextran, carboxymethylcellulose, cellulose sulfate, starch
sulfate, lignosulfonates, gum karaya; polygalacturonic acid,
polyglucuronic acid, polyguluronic acid, polymannuronic acid and
copolymers thereof, chondroitin sulfate, heparin, heparan sulfate,
hyaluronic acid, dermatan sulfate, keratan sulfate; and
derivatives of starch, amylose, amylopectin, cellulose, guaran, gum arabic,
gum karaya, guar gum, pullulan, xanthan, dextran, curdlan, gellan,
carubin, agarose, chitin, and chitosan having the following functional
groups in various degrees of substitution:
carboxymethyl and carboxyethyl, carboxypropyl, 2-carboxyvinyl,
2-hydroxy-3-carboxypropyl, 1,3-dicarboxyisopropyl, sulfomethyl,
2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 5-sulfopentyl,
2-hydroxy-3-sulfopropyl, 2,2-disulfoethyl, 2-carboxy-2-sulfoethyl,
maleate, succinate, phthalate, glutarate, aromatic and aliphatic
dicarboxylates, xanthogenate, sulfate, phosphate, 2,3-dicarboxy,
N,N-di(phosphatomethyl)aminoethyl, N-alkyl-N-phosphatomethyl-aminoethyl,
it being possible for these derivatives as well to contain nonionic
functional groups in various degrees of substitution, such as, for
example, methyl, ethyl, propyl, isopropyl, 2-hydroxyethyl, 2-hydroxypropyl
and 2-hydroxybutyl groups and also esters with alipahtic carboxylic acids
(C.sub.2 to C.sub.18)
and of the formula (X)
##STR3##
where n=5 to 5.times.10.sup.5 ; and R.sup.1, X, A and Y are each identical
or different and defined as follows:
R.sup.1 =H or CH.sub.3 ;
X=O or NH;
A=branched or linear (C.sub.1 -C.sub.18)-alkylenes or arylenes, e.g.
phenylene or naphthylene;
Y=SO.sub.3, COO, N.sym.R.sup.3.sub.2 --A--COO, N.sym.R.sup.3.sub.2
--A--SO.sub.3.sym., N.sym.R.sup.3.sub.2 --A--PO(OH)O.sym. where R.sup.3
=C.sub.1 -C.sub.8 -alkyl;
and also copolymers consisting of monomers of the abovementioned compounds
and one or more of the following monomers in varying composition: acrylic
acid, methacrylic acid, acrylic acid alkyl-(C.sub.1 -C.sub.15)-ester,
methacrylic acid alkyl(C.sub.1 -C.sub.18) ester, glycidyl methacrylate,
acrylamide, acrylonitrile, methacrylonitrile, ethylene, styrene,
.alpha.-methylstyrene, styrenesulfonic acid, butadiene, butene, isoprene,
vinyl chloride, propylene, maleic anhydride, maleic acid, maleic acid
monoalkyl(C.sub.1 -C.sub.18) or dialkyl-(C.sub.1 -C.sub.18) ester,
alkyl-(C.sub.1 -C.sub.18) vinyl ether, vinyl alcohol, vinyl acetate,
vinylbutyral, vinylimidazole, N-vinyl-2-caprolactam, N-vinylpyrrolidone,
mono- or dialkylated (C.sub.1 -C.sub.30) N-vinylpyrrolidone,vinylsulfonic
acid, diallyidimethylammonium chloride, vinylidene chloride, poly(ethylene
glycol) methacrylate, poly(ethylene glycol) acrylate;
d) a carboxyl- and/or sulfo-containing polyester;
A.sup.2 is an acid of formulae (I) to (VIII);
an acid of formula (IX)
##STR4##
in which R.sup.4 and R.sup.5 are as defined above;
or a heteroaromatic mono or dicarboxylic acid;
or by reacting an acid A.sup.1 as defined in c) or d) with an acid A.sup.2
in the definition of the formulae (I) to (IX) in which RI to R.sup.6 have
the definitions specified above and in addition the definitions
(C.sub.1 -C.sub.18)-alkoxy, hydroxyl, amino, (C.sub.1 -C.sub.18)alkylamino,
di(C.sub.1 -C.sub.18)alkylamino, (C.sub.1 -C.sub.18)alkylene-NR.sup.7
R.sup.8, in which R.sup.7 and R.sup.8 are hydrogen or C.sub.1 -C.sub.8
-alkyl; and the cation of the metal is divalent or trivalent.
The preparation of the metal carboxylates and metal sulfonates in an
aqueous alkaline medium is judiciously performed at a temperature between
0 and 1 00.degree. C, preferably between 10 and 90.degree. C., and, in
particular, between 15 and 85.degree. C., under superatmospheric pressure
if desired.
In the case of a divalent metal, the acids A.sup.1 and A.sup.2 employed are
different.
The water-soluble metal salt, the acid A.sup.1 and the acid A.sup.2 are
judiciously each employed in approximately equimolar amounts; in the case
of the acids, there may be deviations of in each case up to 90 mol %.
The water-soluble metal salt can, however, also be added in an excess: for
example, in a from 1.1 to 6 times molar excess per carboxylate or
sulfonate radical. Compounds of the formula (1)
A.sup.10 --M.sup.2 --A.sup.20 (1)
may be formed, where M.sup.2 is the divalent metal,
A.sup.10 is the acid radical of the acid A.sup.1 and
A.sup.20 is the acid radical of the acid A.sup.2, or else, exclusively or
partly, a mixture of the compounds of the formulae A.sup.10 --M.sup.2
--A.sup.10 and A.sup.20 --M.sup.2 --A.sup.20 is formed.
In the case of a trivalent metal the water-soluble metal salt, the acid
A.sup.1 and the acid A.sup.2 can be employed in the same proportions as
described above for divalent metals. In this case, the third ligand of the
trivalent metal is a hydroxyl group.
In this case, the acids A.sup.1 and A.sup.2 employed can be identical or
different, and it is possible for compounds of the formula (2)
##STR5##
to be formed
where A.sup.10 =acid radical of the acid A.sup.1,
A.sup.20 =acid radical of the acid A.sup.2 and
M.sup.3 =trivalent metal.
Where the acids A.sup.1 and A.sup.2 employed are identical, A.sup.10
=A.sup.20
Where the acids A.sup.1 and A.sup.2 employed are different, i is possible
for compounds of the formula (2) having correspondingly different acid
radicals A.sup.10 and A.sup.20 to be formed. However, it is also possible
that, partly or exclusively, a mixture of the compounds (A.sup.10).sub.2
M.sup.3 OH and (A.sup.20).sub.2 M.sup.3 OH is formed.
In the case of a trivalent metal it is, however, also possible to employ
the acids A.sup.1 and A.sup.2 and the metal salt in a molar ratio of about
2:1:1 or 1:2:1, in which case there may be deviations of in each case up
to 90 mol % between the acids. In this case it is also possible for the
third ligand of the trivalent metal to be an acid radical of the acid
A.sup.1 or A.sup.2. Here again, the water-soluble metal salt can be
employed, for example, in a from 1.1 to 6 times molar excess per
carboxylate or sulfonate group. It is also possible here for a mixture of
two or more of the compounds (A.sup.10).sub.3 M.sup.3, (A.sup.10).sub.2
(A.sup.20)M.sup.3, (A.sup.20).sub.2 (A.sup.10)M.sup.3 and
(A.degree.).sub.3 M.sup.3 to be formed if such a mixture precipitates more
rapidly from the aqueous solution than does the compound of the formula
(2a)
A.sup.10 A.sup.20 A.sup.30 M.sup.3 (2a)
where A.sup.30 =acid radical A.sup.10 or A.sup.20.
In particular when the alkaline medium, for example the sodium hydroxide
solution, is employed in excess, acid radicals in the said mixture can be
replaced by OH.
Preferred metal cations M.sup.2+ are Zn.sup.2+, Fe.sup.2+, Co2+, Mn.sup.2+,
N?2+, Cu.sup.24, Mg.sup.2+, Ca.sup.2+,Sr.sup.2+ and Ba.sup.2+.
Preferred metal cations M.sup.3+ are Al.sup.3+, Fe.sup.3+, Mn.sup.3+ and
Co.sup.3+.
Water-soluble metal salts employed are preferably salts of said cations
with anions from the group consisting of fluoride, chloride, bromide,
sulfate, hydrogen sulfate, carbonate, hydrogencarbonate, nitrate and
hydroxide with which sufficient water-solubility in alkaline solution is
provided. The pH of the alkaline solution is adjusted to from 7.5 to 13
using a metal hydroxide M'OH, M.sup.2 (OH).sub.2 or M.sup.3 (OH).sub.3,
preferably NaOH. It is also possible to employ the above-described metal
cations directly in the form of their hydroxides.
A judicious procedure is to slurry the acids A.sup.1 and A.sup.2 in water,
adjust said pH using NaOH, and meter in a solution of water-soluble metal
salt. The desired product usually precipitates and is isolated and dried.
Preferred acids A.sup.1 in the context of the present invention are
##STR6##
##STR7##
c) poly(methacrylic acid), poly(styrenesulfonic acid),
poly(ethylenesulfonic acid), poly(styrenesulfonic acid-co-maleic acid
1:1),
d) polyester consisting of the reaction product of the individual
components i), ii) and iii) and also, if desired, iv) and, if desired, v),
where
i) is a dicarboxylic acid or a reactive derivative of a dicarboxylic acid
which is free from sulfo groups,
ii) is a difunctional aromatic, aliphatic or cycloaliphatic sulfo compound
whose functional groups are hydroxyl or carboxyl, or hydroxyl and
carboxyl,
iii) is an aliphatic, cycloaliphatic or aromatic diol, a polyether diol or
a polycarbonate diol,
iv) is a polyfunctional compound (functionality >2), whose functional
groups are hydroxyl or carboxyl, or hydroxyl and carboxyl, and
v) is a monocarboxylic acid or a sulfo-containing monoalcohol.
Particularly preferred acids A.sup.1 from groups a) to d) are:
##STR8##
c) poly(methacrylic acid), poly(styrenesulfonic acid), poly(styrenesulfonic
acid-co-maleic acid 1:1);
d) a polyester of dimethyl-5-sulfoisophthalic acid, terephthalic acid,
isophthalic acid and neopentyl glycol, propylene glycol and ethylene
glycol;
a polyester of 5-suffoisophthalic acid, terephthalic acid, isophthalic acid
and neopentyl glycol, trimethyloipropane and ethylene glycol;
a polyester of 5-sulfoisophthalic acid, terephthalic acid, isophthalic
acid, cyclohexane-1,3-dicarboxylic acid and neopentyl glycol and ethylene
glycol, and
a polyester of 5sulfoisophthalic acid, terephthalic acid, isophthalic acid,
cyclohexane-1,3-dicarboxylic acid and ethylene glycol, propylene glycol
and isethionic acid.
Preferred acids A.sup.2 in the context of the present invention are
##STR9##
##STR10##
Particularly preferred metal carboxylates and metal sulfonates for the
purposes of the present invention are compounds of the formula (1) in
which
A.sup.10 is 4-tert-butylbenzoate, poly(ethylenesulfonate),
poly(styrenesulfonate), poly(methacrylate), diphenyl disulfide
2,2'-dicarboxylate,
A.sup.20 is 4-tert-butylbenzoate, diphenyl disulfide 2,2'-dicarboxylate,
salicylate and M.sup.2+ is Zn.sup.2+,
or a compound of the formula (2) in which
A.sup.10 and A.sup.20 are as defined above,
A.sup.30 is OH, poly(methacrylate), poly(styrenesulfonate),
poly(ethylenesulfonate), salicylate or diphenyl disulfide
2,2'-dicarboxylate, and
M.sup.3+ is Al.sup.3+.
The molar mass of the polyanion-forming compounds of group c) can vary
within wide limits, for example from M.sub.w =1000 g/mol to M.sub.w =100
000 000 g/mol.
The carboxyl- and/or sulfo-containing polyesters of group d) are described,
for example, in EP-A.sup.2 -0 644 463, especially in the Preparation
Examples therein under 1.1.
The metal carboxylates and metal sulfonates used in accordance with the
invention can be matched precisely to the particular resin/toner system. A
further factor is that the compounds employed in accordance with the
invention are free-flowing and possess high and particularly constant
charge control properties, good thermal stabilities and good
dispersibilities. A further technical advantage of these compounds is that
they are inert toward the various binder systems and can therefore be
employed widely, it being particularly significant that they are not
dissolved in the polymer matrix but rather are present as small, very
finely divided solid structures.
Dispersion means the distribution of one substance within another, i.e. in
the context of the invention the distribution of a charge control agent in
the toner binder, powder coating binder or electret material.
It is known that crystalline substances in their coarsest form are present
as agglomerates. To achieve homogeneous distribution within the binder,
these agglomerates must be disrupted by the dispersing operation into
smaller aggregates, or ideally, into primary particles. The particles of
charge control agent present in the binder following dispersion should be
smaller than 1 .mu.m, preferably smaller than 0.5 .mu.m, with a narrow
particle size distribution being of advantage.
For the particle size, defined by the d.sub.50 value, there are optimum
ranges of activity depending on the material. For instance, coarse
particles (-1 mm) can in some cases not be dispersed at all or can be
dispersed only with considerable investment of time and energy, whereas
very fine particles in the submicron range harbor a heightened safety
risk, such as the possibility of dust explosion.
The particle size and form is established and modified either by the
synthesis and/or by aftertreatment. The required property is frequently
possible only through control of the treatment, such as milling and/or
drying. Various milling techniques are suitable for this purpose. Examples
of advantageous technologies are airjet mills, cutting mills, hammer
mills, bead mills and impact mills.
The binder systems mentioned in connection with the present invention are,
typically, hydrophobic materials. High levels of water in the charge
control agent can either oppose wetting or else promote dispersion
(flushing). The practicable moisture content is therefore specific to the
particular material.
The compounds employed in accordance with the invention feature the
following chemical/physical properties:
The water content, determined by the Karl-Fischer method, is between 0.01%
and 30%, preferably between 0.05 and 25% and, with particular preference,
between 0.05 and 20%, it being possible for the water to be in adsorbed
and/or bonded form, and for its proportion to be adjusted by the action of
heat at up to 200.degree. C. and reduced pressure down to 10.sup.-8 torr
or by addition of water.
The particle size, determined by means of evaluation by light microscope or
by laser light scattering, and defined by the devalue, is between 0.01
.mu.m and 1000 .mu.m, preferably between 0.1 and 500 .mu.m, and with very
particular preference between 0.2 and 400 .mu.m.
It is particularly advantageous if milling results in a narrow particle
size fraction. Preference is given to a range .DELTA.(d.sub.95 -d.sub.50)
of less than 500 .mu.m, in particular less than 200 .mu.m.
The metal carboxylates and metal sulfonates employed in accordance with the
invention can also be combined with further positive or negative charge
control agents in order to obtain good performance chargeabilities, the
overall concentration of these charge control agents being between 0.01
and 50% by weight, preferably between 0.1 and 5% by weight, based on the
overall weight of the electrophotographic toner, developer, powder or
powder coating material.
Examples of suitable further charge control agents are: triphenylmethane;
ammonium and immonium compounds, iminiumcompounds, fluorinated ammonium
and fluorinated immonium compounds; biscationic acid amides; polymeric
ammonium compounds; diallylammonium compounds; aryl sulfide derivatives,
phenol derivatives; phosphonium compounds and fluorinated phosphonium
compounds; calix(n)arenes, cyclically linked oligosaccharides
(cyclodextrins) and their derivatives, especially boric ester derivatives,
interpolyelectrolyte complexes (IPECs); polyester salts; benzimidazolones;
azines, thiazines or oxazines, which are listed in the Colour Index as
Pigments, Solvent Dyes, Basic Dyes or Acid Dyes, or metal azo complex
dyes.
The metal carboxylates and metal sulfonates used in accordance with the
invention and, if desired, further charge control agents are incorporated
individually or in combination with one another in a concentration of from
0.01 to 50% by weight, preferably from 0.5 to 20% by weight, particularly
preferably from 0.1 to 5.0% by weight, based on the overall mixture, into
the binder of the respective toner, developer, coating material, powder
coating material, electret material or of the polymer which is to be
electrostatically separated, said incorporation being homogeneous and
taking place, for example, by means of extrusion or kneading, beadmilling
or using an Ultra-Turrax (high-speed stirrer). In this context the
compounds employed in accordance with the invention can be added as dried
and milled powders, dispersions or solutions, press cakes, masterbatches,
preparations, made-up pastes, as compounds applied from aqueous or non
aqueous solution to appropriate carriers such as silica gel, TiO.sub.2,
Al.sub.2 O.sub.3 or carbon black, for example, or mixed with such
carriers, or added in some other form. Similarly, the compounds used in
accordance with the invention can also in principle be added even during
the preparation of the respective binders, i.e., in the course of their
addition polymerization, polyaddition or polycondensation.
The present invention additionally provides an electrophotographic toner
comprising a customary binder, for example a styrene, styrene-acrylate,
styrene-butadiene, acrylate, acrylic, polyester or epoxy resin or a
combination of the last two, and from 0.01 to 50% by weight, preferably
from 0.5 to 20% by weight, and, with particular preference, from 0.1 to 5%
by weight, based in each case on the overall weight of the
electrophotographic toner, and at least one metal carboxylate or metal
sulfonate, alone or in combination with one or more of the above-described
additional charge control agents.
The electrophotographic toner can additionally comprise from 1 to 10% by
weight, preferably from 2 to 8% by weight, of a colorant, for example, a
dye, an organic or inorganic color pigment or a black pigment, such as
carbon black, for example.
The present invention also provides a powder coating material comprising a
customary binder, such as a urethane, acrylic, polyester or epoxy resin or
a combination thereof, and from 0.01 to 50% by weight, preferably from 0.5
to 20% by weight and, with particular preference, from 0.1 to 5% by
weight, based in each case on the overall weight of the powder coating
material, of at least one metal carboxylate or metal sulfonate, alone or
in combination with one or more of the above-described additional charge
control agents. The powder coating material can additionally contain from
1 to 10% by weight, preferably from 2 to 8% by weight, of a colorant, for
example a dye, an organic or inorganic color pigment or a black pigment,
such as carbon black, for example.
EXAMPLES
In the examples below, parts and percentages are by weight.
Preparation Example 1
7.44g of 4-tert-butylbenzoic acid (0.0413 mol) were suspended in 400 ml of
deionized water, 24.8 ml of 10% strength NaOH solution (0.062 mol) were
added, and the mixture was stirred at room temperature until the organic
acid had dissolved. Then a solution of 6.64 g of aluminum sulfate hydrate
(0.0207 mol) in 40 ml of deionized water was added dropwise over the
course of 10 minutes. A fine white precipitate formed. After the end of
addition of aluminum sulfate, the precipitate was stirred for 15 minutes,
then filtered off with suction, washed several times with deionized water
and finally dried at 60.degree. C. and 100 mbar for 24 h.
Yield: 7.6 g (92% of theory).
Elemental analysis:
Calculated: 66.3% C, 6.8% H, 20.1% 0, 6.8% Al
Found: 60.9% C, 6.4% H, 17.0% 0, 8.1% Al
DTA: no decomposition up to 400.degree. C.
Thermal analysis (Kofler bench): the substance at 1% in a styrene-acrylate
resin
(.RTM.Dialec) shows virtually no discoloration up to 250.degree. C.
pH: 5.4.+-.0.8
Conductivity: 1100.+-.200 .mu.S/cm
H.sub.2 O content (Karl-Fischer method): 1.3.+-.0.3%
Capacitance (1 kHz): 18.6 pF
.epsilon.(1 kHz): 0.075
tan.delta.(1 kHz): 4.2
Spec. resistance: 10.sup.15 .OMEGA.cm
Crystallinity: very high crystallinity (>95%, by X-ray); numerous sharp
reflection peaks between 2theta 5.degree. and 35.degree. (main peaks:
6.6.degree., 7.00, 15.2.degree. and 21.40 and 21.70)
IR: v=3700 cm.sup.-1, 3660-3100, 2960,2900, 2860, 1690,1600, 1560, 1510,
1430, 1370, 1280, 1200, 1110, 1020, 990, 860, 790, 720.
Particle size distribution: d.sub.50 =14.5 .mu.m, d.sub.45 =48.8 .mu.m.
Preparation Example 2
6.48 g of 4-tert-butylbenzoic acid (0.036 mol) were suspended in 4.68 g of
Na-poly-(ethylenesulfonate) (0.036 mol) in 400 ml of deionized water, and
15.4 ml of 10% strength NaOH-solution (0.036 mol) were added. The mixture
was stirred at room temperature until all of the constituents had
dissolved. A solution of 10 9 of zinc chloride (0.072 mol) in 50 ml of
deionized water was then added dropwise to the first solution, giving a
white precipitate. This precipitate was stirred for 15 minutes then
filtered off on a suction filter, washed several times with deionized
water and dried at 60.degree. C. and 100 mbar for 24 h.
Yield: 8.0 9 (64% of theory).
DTA: endothermic peaks at 75.degree. C. and 205.degree. C.
Capacitance (1 kHz): 529 pF
.epsilon.(1 kHz): 25
Spec. resistance: <5.times.10.sup.6 .OMEGA.cm
H.sub.2 O-content: 3.7%
Preparation Example 3
5.02 g of salicylic acid (0.036 mol) were suspended in 12.96 g of
Na-poly-(methacrylate) (0.036 mol) in 400 ml of deionized water, and 14.4
ml of 10% strength NaOH-solution (0.036 mol) were then added with stirring
at room temperature. A solution of 10 g of zinc chloride (0.072 mol) in 50
ml of deionized water was then added dropwise to the first, clear
solution, giving a white precipitate. This precipitate was stirred for 15
minutes then filtered off on a suction filter, washed several times with
deionized water and dried at 60.degree. C. and 100 mbar for 24 h.
Yield: 6.0 9 (58% of theory).
DTA: melting peak at 114.degree. C.
Crystallinity: virtually X-ray amorphous (one very broad peak at
2theta=9.7.degree.)
Preparation Example 4
7.44 g of diphenyl disuffide 2,2'-dicarboxylic acid (0.0207 mol) together
with 2.89 g of salicylic acid (0.0207 mol) were suspended in 400 ml of
deionized water, and 26.8 ml of 10% strength NaOH solution (0.062 mol)
were added at room temperature with stirring. After the two components of
the suspension had dissolved, a solution of 20 g of aluminum sulfate
hydrate (0.062 mol) in 80 ml of deionized water was added dropwise over
the course of 10 minutes. A slightly brownish, fine precipitate formed.
This precipitate was stirred for 15 minutes, washed several times with
deionized water, filtered off on a suction filter and finally dried at
60.degree. C. and 100 mbar for 24 h.
Yield: 9.1 g (94% of theory).
Further preparation examples, which were synthesized in analogy to the
above-described Examples 1 to 4, are reproduced in Table I below.
TABLE 1
Ex. No. Metal salt Anion A1 Anion A2 Anion A3
5 [Al.sub.2 (SO.sub.4).sub.3 ] Na-PMAA 4-t-butylbenzoic
acid Na-PMAA
6 [Al.sub.2 (SO.sub.4).sub.3 ] Na-PES 4-t-butylbenzoic
acid Na-PES
7 [Al.sub.2 (SO.sub.4).sub.3 ] Na-P[SSA-co-MA] 4-t-butylbenzoic acid
Na-P[SSA-
co-MA]
8 [Al.sub.2 (SO.sub.4).sub.3 ] 4-t-butylbenzoic acid 4-t-butylbenzoic
acid Na-PMAA
9 [Al.sub.2 (SO.sub.4).sub.3 ] 4-t-butylbenzoic acid 4-t-butylbenzoic
acid Na-PSSA
10 [Al.sub.2 (SO.sub.4).sub.3 ] 4-t-butylbenzoic acid
4-t-butylbenzoic acid Na-PES
11 [Al.sub.2 (SO.sub.4).sub.3 ] 4-t-butylbenzoic acid
4-t-butylbenzoic acid Na-P[SSA-
co-MA 1:1]
12 [Al.sub.2 (SO.sub.4).sub.3 ] 1M Na-PMAA
4-t-butylbenzoic acid 1M NaOH
13 [Al.sub.2 (SO.sub.4).sub.3 ] Na-PSSA
4-t-butylbenzoic acid NaOH
14 [ZnCl.sub.2 ] Na-PMAA 4-t-butylbenzoic acid --
15 [ZnCl.sub.2 ] Na-PSSA 4-t-butylbenzoic acid --
16 [ZnCl.sub.2 ] Na-P[SSA-co-MA 4-t-butylbenzoic acid --
1:1]
17 [ZnCl.sub.2 ] Na-PSSA salicylic acid --
18 [ZnCl.sub.2 ] Na-PES salicylic acid --
19 [ZnCl.sub.2 ] Na-PMAA % diphenyl disulfide --
dibenzoic acid
20 [ZnCl.sub.2 ] Na-PSSA 1/2 diphenyl disulfide --
dibenzoic acid
21 [ZnCl.sub.2 ] Na-PES 1/2 diphenyl disulfide --
dibenzoic acid
22 [ZnCl.sub.2 ] Na-P[SSA-co-MA 1/2 diphenyl disulfide
1:1] dibenzoic acid
23 [Al.sub.2 (SO.sub.4).sub.3 ] 1/2 diphenyl disulfide 1/2 diphenyl
disulfide 4-t-butyl-
dibenzoic acid dibenzoic acid benzoic acid
24 [Al.sub.2 (SO.sub.4).sub.3 ] 1/2 diphenyl disulfide salicylic
acid salicylic acid
dibenzoic acid
25 [Al.sub.2 (SO.sub.4).sub.3 ] 4-t-butylbenzoic acid 1/2 diphenyl
disulfide 4-t-butyl-
dibenzoic acid benzoic acid
26 [Al.sub.2 (SO.sub.4).sub.3 ] 1/2 diphenyl disulfide 1/2 diphenyl
disulfide NaOH
dibenzoic acid dibenzoic acid
27 [Al.sub.2 (SO.sub.4).sub.3 ] 4-t-butylbenzoic acid 1/2 diphenyl
disulfide NaOH
dibenzoic acid
28 [Al.sub.2 (SO.sub.4).sub.3 ] 1/2 diphenyl disulfide salicylic
acid NaOH
dibenzoic acid
29 [ZnCl.sub.2 ] 4-t-butylbenzoic acid 1/2 diphenyl disulfide --
dibenzoic acid
30 [ZnCl.sub.2 ] 1/2 diphenyl disulfide salicylic acid --
dibenzoic acid
31 [ZnCl.sub.2 ] ionic polyester 4-t-butylbenzoic acid --
32 [ZnCl.sub.2 ] ionic polyester salicylic acid --
Na-PMAA = sodium-polymethacrylic acid
Na-PSSA = sodium polystyrenesulfonic acid
Na-PES = sodium polyethylene sulfonic acid
Na-P[SSA-co-MA 1:1] = sodium-poly(styrenesulfonic acid-co-maleic acid 1:1)
Ionic polyester = consists of dimethyl-5-sulfoisophthalic acid,
terephthalic acid, isophthalic acid and neopentyl glycol, propylene glycol
and ethylene glycol.
Characterization of the compound from Preparation Example 14:
Elemental analysis:
Calculated: 55.0% C, 5.5% H. 19.5% O, 20.0% Zn
Found: 47.6% C, 5.5% H, 23.5% O, 21.0% Zn
Capacitance (1 kHz): 263 pF
.epsilon.(1 kHz): 2.12
Spec. resistance: 7.times.10.sup.7 .OMEGA.cm
H.sub.2 O content: 8.0%
Characterization of the compound from Preparation Example 17:
Crystalinity: 70% crystallinity (X-ray analysis); numerous sharp reflection
peaks between 2theta 5.degree. and 350 (main peaks: 7.60, 9.70, 14.90,
15.50 and also 26.0.degree. and 30.00)
H.sub.2 O content: 5.6%
Use Examples
In the use examples below the following toner binders and carriers are
employed:
Toner binders:
Resin 1: 60:40 styrene-methacrylate copolymer
Resin 2: Bisphenol-based polyester (OAlmacryl resin)
Carriers:
Carrier 1: styrene-methacrylate copolymer-coated magnetite particles of
size 50 to 200 .mu.m (bulk density 2.62 g/cm.sup.3) (FBM 100A; from Powder
Techn.)
Carrier 2: silicone-coated ferrite particles of size 50 to 100 .mu.m (bulk
density 2.75 glcm.sup.3) (FBM 96-1 1A; from Powder Techn.)
Use Example 1
1 part of the compound of the formula
##STR11##
is incorporated homogeneously using a kneader over the course of 45 minutes
into 99 parts of a toner binder (60:40 styrene-metahcrylate copolymer,
resin 1, .RTM.Dialec S 309). The composition is then ground on a
laboratory universal mill and subsequently classified in a centrifugal
classifier. The desired particle fraction (4 to 25 .mu.m) is activated
with a carrier (Carrier 1).
Use Examples 2 to 33
1 part of each metal carboxylate or metal sulfonate is incorporated into
the respective resin using a kneader, as described in Use Example 1.
Electrostatic testing:
Measurement is carried out on a customary q/m measurement stand. By using a
sieve having a mesh size of 50 .mu.m it is ensured that no carrier is
entrained when the toner is blown out. Measurements are made at 50%
relative atmospheric humidity. The q/m values [pC/g] are measured as a
function of the activation period. The q/m values of Use Examples 2 to 33
are given in Table 2. The amounts of respective metal carboxylate or metal
sulfonate are in each case 1% by weight. q/m values for Use Example 1:
Activation period
[min] Charge q/m [.mu.C/g]
5 -15.8
10 -23.5
30 -37.0
120 -53.3
24 h -68.6
TABLE 2
Com-
pound
from
Prepara-
tion q/m [.mu.C/g] after activation time of
Ex. No. Resin Carrier 5 min 10 min 30 min 120 min
2 1 1 -13.4 -16.2 -21.7 -28.8
3 1 1 -17.0 -16.6 -17.9 -18.0
4 1 1 -12.7 -14.8 -17.8 -20.1
5 1 1 -4.6 -6.5 -11.8 -23.3
6 1 1 -4.5 -6.1 -10.1 -17.6
7 1 1 -4.3 -5.5 -9.3 -16.1
8 1 1 -5.3 -8.3 -14.9 -27.5
9 1 1 -6.1 -6.3 -9.1 -11.9
10 1 1 -7.5 -8.7 -13.9 -21.6
11 1 1 -5.5 -6.4 -94 -15.4
12 1 1 -6.1 -6.5 -11.0 -19.4
13 1 1 -5.1 -5.9 -9.0 -12.3
14 1 1 -10.3 -13.9 -19.9 -25.3
15 1 1 -9.3 -10.5 -17.2 -27.1
16 1 1 -6.9 -10.2 -15.0 -22.9
17 1 1 -10.0 -9.2 -9.4 -10.7
18 1 1 -8.6 -7.0 -6.9 -8.5
19 1 1 -10.7 -13.5 -17.8 -20.7
20 1 1 -4.0 -6.0 -8.2 -11.2
21 1 1 -4.0 -5.7 -7.9 -12.0
22 1 1 -6.8 -11.1 -15.4 -19.0
23 1 1 -6.1 -7.0 -10.9 -17.2
24 1 1 -5.9 -6.7 -10.1 -15.7
25 1 1 -5.2 -6.8 -11.4 -22.2
26 1 1 -4.0 -6.0 -9.5 -15.3
27 1 1 -5.3 -6.7 -10.9 -19.3
28 1 1 -5.1 -7.0 -11.5 -18.4
29 1 1 -8.9 -13.2 -18.1 -23.3
30 1 1 -4.8 -6.0 -8.7 -12.0
31 1 1 -4.4 -5.6 -8.5 -14.8
32 2 2 -16.3 -14.7 -13.4 -11.8
14 2 2 -22.0 -20.6 -22.6 -24.5
Use Example 34:
The procedure of Use Example 1 is repeated with the further incorporation,
to one part of the compound from Use Example 1, of one part of C.I.
Solvent Blue 125 (see Comparative Example 1). The following q/m values are
measured as a function of the activation period:
Activation period [min] Charge q/m [.mu.C/g]
5 -11.3
10 -14.9
30 -21.7
120 -26.6
The high positive intrinsic triboelectric effect of C.I. Solvent Blue 125
(see Example 1) can be reversed markedly in polarity to negative by adding
1 part of a compound from Use Example 1.
Use Example 35:
The procedure of Use Example 1 is repeated with the further incorporation,
to one part of the compound from Use Example 1, of 5 parts of carbon black
125 (Mogul L, Cabot, see Comparative Example 2). The following qim values
are measured as a function of the activation period:
Activation period
[min] Charge q/m [.mu.C/g]
5 -13.0
10 -14.6
30 -14.9
120 -20.0
24 h -30.7
Use Example 36:
The procedure of Use Example 1 is repeated but using only 0.5 part rather
than 1 part of the compound from Use Example 1. The following qim values
are measured as a function of the activation period:
Activation period [min] Charge q/m [.mu.C/g]
5 -8.5
10 -15.7
30 -27.3
120 -44.3
24 h -63.7
Use Example 37:
The procedure of Use Example 1 is repeated but using 2 parts rather than 1
part of the compound from Use Example 1. The following q/m values are
measured as a function of the activation period:
Activation period
[min] Charge q/m [.mu.C/g]
5 -19.3
10 -27.7
30 -45.0
120 -55.3
24 h -75.5
Use Example 38:
1 part of the compound from Use Example 1 was incorporated homogeneously
into 99 parts of a powder coating binder (.RTM.Crylcoat 430) as described
for the abovementioned use examples. The triboelectric spraying of the
powders (powder coating materials) was carried out with a spraying
apparatus such as the .RTM.TriboStar from Intec (Dortmund, Germany),
having a standard spraying pipe and a star-shaped interior rod, at maximum
powder throughput with a spray pressure of 3 and 5 bar. For this purpose,
the article to be sprayed was suspended in a spray booth and sprayed
directly from the front from a distance of about 20 cm without further
movement of the spraying apparatus. The respective charge of the sprayed
powder was subsequently measured with a device from Intec for measuring
the triboelectric charge of powders. For the measurement, the measuring
antenna of the device was held directly in the cloud of powder emerging
from the spraying device. The current strength resulting from the
electrostatic charge of powder coating material or powder was indicated in
.mu.A. The deposition rate was subsequently determined, in %, by
differential weighing of sprayed and deposited powder coating material.
Pressure [bar] Current [.mu.A] Deposition rate [%]
3 0.3-0.5 50
5 1.2-1.7 48
Use Example 39
The compound from Use Example 1 is treated as in Use Example 1 except that
the sample of the subsequent qim measurement is stored not at the usual
relative atmospheric humidity (between 35 and 65%) but instead at a
relative atmospheric humidity of 10% (25.degree. C.) for 24 h, this
humidity being established in a climatically controlled cabinet (from
Espec).
The following q/m values are measured here as a function of the activation
period:
Activation period [min] Charge q/m [.mu.C/g]
5 -9.5
10 -15.0
30 -25.3
120 -45.4
It is evident that the relatively strong negative triboelectric effect of
the compound from the Use Example 1 is maintained.
Use Example 40
The procedure of Use Example 39 is repeated, with the sample being stored
in the climatically controlled cabinet at a relative atmospheric humidity
of 90% (25.degree. C.) for 24 h. The following q/m values are measured
here as a function of the activation period
Activation period [min] Charge q/m [.mu.C/g]
5 -9.5
10 -10.8
30 -13.7
120 -19.1
Here again, the marked negative triboelectric effect of the compound is
maintainted.
Comparative Example 1:
The procedure of Use Example 1 is repeated but in this case 1 part of C.I.
Solvent Blue 125 is incorporated instead of 1 part of a compound from Use
Example 1. The following q/m values are measured as function of the
activation period:
Activation period [min] Charge q/m [.mu.C/g]
5 -0.1
10 +0.4
30 +2.7
120 +10.4
24 h +29.3
The pronounced positive intrinsic triboelectric effect of the blue colorant
is clearly evident.
Comparative Example 2:
The procedure of Use Example 1 is repeated but in this case 5 parts of
carbon black (.RTM.Mogul L, Cabot) are incorporated instead of 1 part of
the compound from Use Example 1. The following q/m values are measured as
function of the activation period:
Activation period [min] Charge q/m [.mu.C/g]
5 -14.5
10 -15.2
30 -14.5
120 -7.3
24 h +3.4
It is evident that the carbon black employed shifts the negative charge in
the positive direction to a marked extent.
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